Due to energy requirements, especially electrical consumption, there is an ever increasing proliferation of the installation of solar panels for energy production. To enable a better use of the solar energy, these solar panels or trackers are provided with a rotation module for their solar orientation. Thanks to the motorization of these rotation modules, the solar panels are continually and automatically reoriented achieving a maximum output.
The rotation modules existing on the market are characterized in that they work, preferably, so that the largest part of the load is axial. A rotation module that must orientate a solar panel zenithally, receives mainly radial loads, so that a large part of the solar projects reject the use of standard rotation modules for zenithal orientation, choosing other means of orientation that are less precise such as linear actuators.
In the state of the art, the following references are known which describe rotation modules for orienting solar panels in their zenith and azimuth axes, jointly or independently:                Patent EP2063200 discloses a two-axis transmission which has independent power units for each axis. The axes are disposed so that they independently allow zenithal and azimuthal movement, the mechanism of which can be implemented in solar panels. As a noteworthy characteristic it discloses the use of a specific conical toothing which makes it possible to reduce the play between the crowns, when they are operating.        Patent US20100229678 discloses a two-axis mechanism with dual transmission and with two independent shafts disposed orthogonally.        Patent CN201232734 discloses a transmission mechanism for a heliostat, the mechanism of which is based on a toothed crown and a screw.        
The rotation modules described in said references are not designed for supporting solar panels with large dimensions so that they do not support well the radial loads whereto the toothed crown is subjected. Indeed, the solar panels or surfaces are mounted on the orientation module, through two horizontal shafts, which are fixed on both sides of the toothed crown in a symmetrical and aligned fashion, for the rotation thereof, and therefore, the zenithal orientation of the panels. Therefore, the entire weight of the structure supported by the solar panels falls on the toothed crown, generating radial loads, proportional to the size and weight of the solar surface.
Another drawback of the current rotation modules is the complexity involved in their assembly within the structural casing, since it must guarantee the robustness of the unit, the perfect alignment of the horizontal shafts, as well as facilitating their subsequent maintenance. For an optimum energy output of the solar panel it must be constantly oriented in accordance with the position of the sun. This implies that the orientation module must act with extreme precision to achieve maximum use of the solar energy. Hence, the toothed crown must slide extremely gently within the structural casing, minimizing the friction and with a good greasing system. Most rotation modules comprise a single greasing system common to the endless screw and to the crown bearings, with the drawbacks that this entails, since the greasing requirements differ for each mechanism. The entry of impurities or foreign particles in the crown bearings may be very harmful for the rotation module and produce important alignments in the solar panels, which would negatively affect the energy output of the solar installation.
To achieve the maximum precision and robustness, all known rotation modules comprise a multitude of intermediate parts, such as bearings and their attachments to the casing and the crown which complicate their assembly, whilst hindering their later maintenance and repair.